Acta Obstet Gynecol Scand 55: 175-177, 1976
SHORT COMMUNICATION
PLASMA RENIN ACTIVITY IN ABORTION Pertti Soveri, Frej Fyhrquist and Olof Widholm From the Unit of Clinical Physiology, The Minerva Institute for Medical Research, (Head: R . Grasbeck), Helsinki, and the Second Department of Gynaecology and Obstetrics (Head: 0. Widholm), The University Central Hospital, Helsinki, Finland
Abstract. Healthy women (N=96) were investigated for changes in plasma renin activity (PRA) in abortion. In spontaneous abortion PRA levels were significantly lower than in induced abortion although higher than in healthy women. These findings may be explained by differences in corpus luteum function and renin production of the fetoplacental unit. Alternatively, prostaglandins released by the contracting uterus in spontaneous abortion may cause PRA suppression, as observed in 9 pregnant women with abortion induced by the intra-amniotic use of prostaglandin Fza.
Little is known about the role of renin in pregnancy and labour in humans. It has been reported that plasma renin activity rises during pregnancy (4, 6, 8, 11, 14) and falls nearly to normal approximately 24 hours after parturition (1, 7, 9). It has also been shown that plasma renin concentration is raised, being highest during the first trimester of pregnancy, having a tendency to fall towards term (7,8). Although all these factors are increased during pregnancy, the importance of this finding is not known. To investigate the possible role of renin in miscarriage, mothers with both spontaneous and induced abortion were studied for the changes in their plasma renin activity and compared with mothers with uncomplicated pregnancy.
at 8-20 weeks of gestation, but did not abort and later had normal deliyeries. Thirty-six subjects were normal controls at 1040 weeks .of gestation. The microscopy of the spontaneous abortions showed no histological abnormalities. All the subjects were on their normal home diet. The blood samples for measuring plasma renin activity were collected the first day the subject came to the clinic and the day following the abortion. The control samples were taken during the subjects’ normal visits to the clinic. All samples were taken after 20 minutes supine position after 12 hours of fasting, at 10-11 a.m. Diet was unrestricted. Plasma renin activity was measured by a radioimmunoassay method (3,4).
7.0-
. .
53
2
6.0-
0
l.5
.c z
5.0-
._ > ._ c
g 4.0-
.-C
E
3.0-
2 2 2.0-
-
a
I
1.0-
Healthy women. luleal phase. mean? S D
(N=341
1
MATERIAL AND METHODS Ninety-six healthy pregnant women aged 1742 years, with no previous history of renal or vascular disturbances were investigated. None of them showed hypertension or fluid retention. Twenty-six subjects had a spontaneous abortion at 9-13 weeks of gestation. The abortions were completed by evacuation and curettage. Twenty-six subjects were taken into the hospital for threatened abortion 12-762862
Acta Obstet Gynecol Scand 55 (1976)
176
P . Soveri et al.
Table I . Plasma renin activity in spontaneous and induced abortion in hedthy btwmen compared to normal pregnancy und non-pregnant women PRA , mean f S.E.M. (ng/ml/hr) Group investigated
N
I . Spontaneous abortion 2. Induced abortion 3. Threatened abortion 4. Normal pregnancy 5. Non-pregnant estrogen phase 6. Non-pregnant luteal phase
26 26 20 31 34
10
Week of gestation 9-13 8-16 8-20 10-20
Significances of differences obtained with Student's r-test: Group I before/after,p
SHORT COMMUNICATION
PLASMA RENIN ACTIVITY IN ABORTION Pertti Soveri, Frej Fyhrquist and Olof Widholm From the Unit of Clinical Physiology, The Minerva Institute for Medical Research, (Head: R . Grasbeck), Helsinki, and the Second Department of Gynaecology and Obstetrics (Head: 0. Widholm), The University Central Hospital, Helsinki, Finland
Abstract. Healthy women (N=96) were investigated for changes in plasma renin activity (PRA) in abortion. In spontaneous abortion PRA levels were significantly lower than in induced abortion although higher than in healthy women. These findings may be explained by differences in corpus luteum function and renin production of the fetoplacental unit. Alternatively, prostaglandins released by the contracting uterus in spontaneous abortion may cause PRA suppression, as observed in 9 pregnant women with abortion induced by the intra-amniotic use of prostaglandin Fza.
Little is known about the role of renin in pregnancy and labour in humans. It has been reported that plasma renin activity rises during pregnancy (4, 6, 8, 11, 14) and falls nearly to normal approximately 24 hours after parturition (1, 7, 9). It has also been shown that plasma renin concentration is raised, being highest during the first trimester of pregnancy, having a tendency to fall towards term (7,8). Although all these factors are increased during pregnancy, the importance of this finding is not known. To investigate the possible role of renin in miscarriage, mothers with both spontaneous and induced abortion were studied for the changes in their plasma renin activity and compared with mothers with uncomplicated pregnancy.
at 8-20 weeks of gestation, but did not abort and later had normal deliyeries. Thirty-six subjects were normal controls at 1040 weeks .of gestation. The microscopy of the spontaneous abortions showed no histological abnormalities. All the subjects were on their normal home diet. The blood samples for measuring plasma renin activity were collected the first day the subject came to the clinic and the day following the abortion. The control samples were taken during the subjects’ normal visits to the clinic. All samples were taken after 20 minutes supine position after 12 hours of fasting, at 10-11 a.m. Diet was unrestricted. Plasma renin activity was measured by a radioimmunoassay method (3,4).
7.0-
. .
53
2
6.0-
0
l.5
.c z
5.0-
._ > ._ c
g 4.0-
.-C
E
3.0-
2 2 2.0-
-
a
I
1.0-
Healthy women. luleal phase. mean? S D
(N=341
1
MATERIAL AND METHODS Ninety-six healthy pregnant women aged 1742 years, with no previous history of renal or vascular disturbances were investigated. None of them showed hypertension or fluid retention. Twenty-six subjects had a spontaneous abortion at 9-13 weeks of gestation. The abortions were completed by evacuation and curettage. Twenty-six subjects were taken into the hospital for threatened abortion 12-762862
Acta Obstet Gynecol Scand 55 (1976)
176
P . Soveri et al.
Table I . Plasma renin activity in spontaneous and induced abortion in hedthy btwmen compared to normal pregnancy und non-pregnant women PRA , mean f S.E.M. (ng/ml/hr) Group investigated
N
I . Spontaneous abortion 2. Induced abortion 3. Threatened abortion 4. Normal pregnancy 5. Non-pregnant estrogen phase 6. Non-pregnant luteal phase
26 26 20 31 34
10
Week of gestation 9-13 8-16 8-20 10-20
Significances of differences obtained with Student's r-test: Group I before/after,p
